SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b46b583cab457a6571369e45a4f5ee211f0885124b8c847fe9cd5b99c1390aa1' 
  AND token = 'tzob8ifXLyGIEPEcqsvJh1BTId0QtLH+i8i1iB1My/o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}